Effect of formulary restriction of cefotaxime usage.

Cefotaxime sodium was assigned to the open formulary for 12 months and then was placed on formulary restriction to evaluate the restriction's effect on rate of use by services and appropriateness of use. Over 18 months, 187 cases (72 before and 115 after restriction) were reviewed. The majority of use (prerestriction and postrestriction) was in the medicine, pediatrics, and surgery services. The postrestriction usage rate for the three services increased significantly. Cefotaxime was used appropriately in 85% of cases during both periods and was not used prophylactically. Appropriateness of use was independent of formulary restriction. During both periods, approximately 76% of patients received cefotaxime for pneumonia, sepsis, meningitis, or immunosuppression. Of 205 infections, gram-negative bacilli accounted for over half of the pathogens isolated. Thus, formulary restriction was ineffective in reducing the rate of cefotaxime usage and had no effect on the appropriateness of usage.